MT True Scale Couplers revisited

[Bill H]

Group:
As I noted in an earlier post to the original TSC thread, I tried modifying the coupler parts in hopes to improve performance. The fingers of the two coupler parts average about .016" in thickness. I tried thinning the >inside< in 0.02 increments with continual testing as I thinned. Once the inside of each finger was thinned to approximately 0.010" ease of coupling improved significantly, there was no longer any "snap" and they coupled with similar ease as the normal MT couplers. I then tested them for disconnects under load and did not experience any at all at the 0.010" thickness. That is the good news.

The bad news was that although the couplers coupled perfectly, without resistance, when perfectly aligned facing each other, in normal operation, given the lateral movement in most cars due to various tolerances in wheel sets, rail gauge etc., the face of the "hook" of the coupler is not sufficiently wide to cover potential lateral tolerances. In other words, if I aligned the two cars facing each other by hand, they would couple perfectly. When I had the cars pushed together by a locomotive, the coupling only occured about 5% of the time, and then only on straight track. Basically the hooks would not engage sufficiently to slide laterally and thence engage. And last, even with the thinned fingers, lateral movement was insufficient and resulted in some 40' NMRA weighted cars rocking on 14" curvatures.

In conclusion, at least for my purposes, the TCS is not going to work. Joe clearly outlined his performance expectations in his original announcement, yet I was hoping that I could adapt them to my operational orientation. I think the lateral movement issue could eventually be solved, but given the very small face of each hook, hands free coupling, at this point seems really problematic.

Kind regards,
Bill

[wcfn100]

Lateral movement can be addressed very easily but not very economically.  Remove the wedge the fingers push against and replace it with one from another pocket making sure it floats around the screw.you're just limited then to how tight you can turn the screw.


Jason

[Mike C]

Group:
As I noted in an earlier post to the original TSC thread, I tried modifying the coupler parts in hopes to improve performance. The fingers of the two coupler parts average about .016" in thickness. I tried thinning the >inside< in 0.02 increments with continual testing as I thinned. Once the inside of each finger was thinned to approximately 0.010" ease of coupling improved significantly, there was no longer any "snap" and they coupled with similar ease as the normal MT couplers. I then tested them for disconnects under load and did not experience any at all at the 0.010" thickness. That is the good news.

The bad news was that although the couplers coupled perfectly, without resistance, when perfectly aligned facing each other, in normal operation, given the lateral movement in most cars due to various tolerances in wheel sets, rail gauge etc., the face of the "hook" of the coupler is not sufficiently wide to cover potential lateral tolerances. In other words, if I aligned the two cars facing each other by hand, they would couple perfectly. When I had the cars pushed together by a locomotive, the coupling only occured about 5% of the time, and then only on straight track. Basically the hooks would not engage sufficiently to slide laterally and thence engage. And last, even with the thinned fingers, lateral movement was insufficient and resulted in some 40' NMRA weighted cars rocking on 14" curvatures.

In conclusion, at least for my purposes, the TCS is not going to work. Joe clearly outlined his performance expectations in his original announcement, yet I was hoping that I could adapt them to my operational orientation. I think the lateral movement issue could eventually be solved, but given the very small face of each hook, hands free coupling, at this point seems really problematic.

Kind regards,
Bill

In other words it's pretty much proto tipically to scale ?

[peteski]

In other words it's pretty much proto tipically to scale ?

Probably so, but unfortunately, even in N scale, our layouts are greatly compressed. So turnouts and curve radii are much sharper than the prototype. So, we need a couplers which will work properly under those conditions.

[Rich_S]

Probably so, but unfortunately, even in N scale, our layouts are greatly compressed. So turnouts and curve radii are much sharper than the prototype. So, we need a couplers which will work properly under those conditions.

That depends on weather your talking main line or yard tracks, but I understand your point. Just as a FYI, we have #5 turnouts at the engine house. We even have one curve track, that if you uncouple a dead engine in the middle of the curve, you have to wrap a chain around both coupler shanks and pull the engine out of the curve, to be able to couple to it. Of note, this is industrial chain that weights about 100 lbs. for a 10' piece. The biggest thing that works against us in N scale, we can't scale down the weight of cars and locomotives, they are so light, instead of coupling they bounce away from each other if the coupler is the least bit tight. Of course it would be hard to handle and support scale weighted equipment, a typical N scale locomotive would weight about 2,500 lbs. good luck picking up that new Kato SDP40F   

[Bill H]

Rich:
The problem with TSC couplers is not that the cars bounce away because they are too light and do not generate sufficient inertia to coupler, the problem is that the coupler faces are too small to deflect sufficiently to allow the couplers to engage. Thinning the fingers to 0.010 solves the click or hard coupling issue, it is just that the coupler faces have to be perfectly facing each other to engage. Joe noted that a slight angle in mounting to encourage the two coupler faces helps just a bit, but it still requires the two cars to be perfectly centered towards each other.

Kind regards,
Bill

[jagged ben]

...The biggest thing that works against us in N scale, we can't scale down the weight of cars and locomotives, they are so light, instead of coupling they bounce away from each other if the coupler is the least bit tight. Of course it would be hard to handle and support scale weighted equipment, a typical N scale locomotive would weight about 2,500 lbs. good luck picking up that new Kato SDP40F   

An N scale model with an appropriate 'scale weight' - i.e. 1/160th the dimensions with the same density as the prototype - would be 1/4096000th the weight, which is to say 1 divided by 160 cubed because that's the formula for volume.  Thus a Kato SDP40F, at about 6 ounces, is about six times heavier in scale than its 265,000lb prototype counterpart.   (This is not surprising, given that the model is filled with solid metal in so many areas where the prototype has empty working space.)   The scale weight of N scale rolling stock is generally near or somewhat above that of a loaded prototype bulk goods car, if NMRA guidelines are followed, or somewhere in between loaded and empty weight on older models with no added weight. 

So, anyway, that is not the problem with coupling...

The problems to my best guess, are:
- our cars don't have brakes
- despite weighing millions of times less, our cars still ride on the same number of bearings, and this completely changes the friction coefficient
- the material characteristics of Delrin and steel at all scales are different
- most importantly, we are simply not simulating anything like true coupler action in N scale, either with the True-Scale couplers or any others.    Expecting coupler faces to deflect off each other in order to facilitate coupling isn't something that's compatible with the notion of accurate scale coupler dimensions, because real couplers don't couple that way.  If you look at the Sargent couplers in HO scale you'll find something that actually models prototype functions.  We don't have anything like that in N scale. (Yet.   )

I finally got a chance to open my True Scale couplers last night.  I put a pair together but haven't installed on any models yet.  I'm baffled by the total lack of coupler swing.  I may just cut off the whiskers and fuse the shanks together for the applications I decide to use these for, which would probably be for passenger locomotive lashups or unit trains.  I think someone else mentioned doing that.  I would rather have the couplers function well when coupled together than worry about coupling and uncoupling operations. 

[MichaelWinicki]

I wonder if the answer is a coupler that is sized in between an MT n-scale coupler and the True Scale, which also fits in a 1015 box.  And if it fit in a truck-mounted coupler box– maybe even better.  But obviously it needs to have more swing than the True Scale coupler.

[Ngineer]

unit trains.  I think someone else mentioned doing that.

I am planning on converting the tiny teeny Atlas ore cars and I am sure that these couplers (MT true scale) will look great. The other couplers (e.g. Accumates) are rather oversized and, more important, the distance between coupled ore cars is wrong with Accumates.

    Javier

[Bill H]

I wonder if the answer is a coupler that is sized in between an MT n-scale coupler and the True Scale, which also fits in a 1015 box.  And if it fit in a truck-mounted coupler box– maybe even better.  But obviously it needs to have more swing than the True Scale coupler.

Michael,
Needs more than swing needs sufficient coupler face width to allow for coupling when cars are not perfectly aligned with each other.
Kind regards,
Bill

[nkalanaga]

Javier:  These should work for your ore cars if they run as a unit train. 

Mine don't, so they got Z 903 couplers, set back so only the coupler itself sticks out.  Much closer coupling than with standard N couplers, and they will still work with regular MTs on the locos.  Mine run as a solid train, but have to be switched for loading, putting 30 cars into four tracks, then pulling them out again.

[Mark5]

I am planning on converting the tiny teeny Atlas ore cars and I am sure that these couplers (MT true scale) will look great. The other couplers (e.g. Accumates) are rather oversized and, more important, the distance between coupled ore cars is wrong with Accumates.

    Javier

Accumates are much smaller than McHenry (McHuge!) and about the same size as MTL. Obviously they are all larger than the new MTL True Scale.

The problem with the Accumates coupling distance is purely on truck mounted couplers. Body mounted as in locos and on the newer body mounted freight cars it is not a problem (at least in terms of the immediate peers MTL and McHenry).

Mark

[garethashenden]

I think that something that is being overlooked in the discussion of these couplers is that the NMRA N scale track standards aren't exactly tight. If you have two tiny couplers that you're trying to line up, you're going to have a lot of trouble if the wheels keep moving side to side. Most people aren't going to be thrilled at the prospect of having to modify just about everything and come up with their own standard just to use a new coupler.

Two things to remember:
1) Micro Trains are not recommending this as a replacement for most couplers. They are suggesting it for unit trains and highly detailed locomotives.
2) Bachmann use their ridiculously huge coupler so that their locomotives and cars will couple reliably and stay coupled. They wanted to remove frustration with couplers from their customer's experience.

[Rich_S]

An N scale model with an appropriate 'scale weight' - i.e. 1/160th the dimensions with the same density as the prototype - would be 1/4096000th the weight, which is to say 1 divided by 160 cubed because that's the formula for volume.  Thus a Kato SDP40F, at about 6 ounces, is about six times heavier in scale than its 265,000lb prototype counterpart.   (This is not surprising, given that the model is filled with solid metal in so many areas where the prototype has empty working space.)   The scale weight of N scale rolling stock is generally near or somewhat above that of a loaded prototype bulk goods car, if NMRA guidelines are followed, or somewhere in between loaded and empty weight on older models with no added weight. 

Ben, Yes I'm not a mathematician, just a dumb locomotive electrician, but I'm not buying it. We are talking dead weight not volume. 5,000 cubic feet of air does not weight the same as 5,000 cubic feet of lead. How much does that 16 cylinder diesel engine weight with 300 gallons of oil and 300 gallons of water on board? Then you have that 5 ton Generator coupled to it. You have 3,000 gallons of diesel fuel, you have 6 tons of traction motors, not even sure what the air compressor weights, but you have to pick it up with a crane. Heck, the starter motors weight 80 lbs and there are two of them. Our models are plastic with some light weight metals used for the electric motor and cast frame. Yes our models do not have breaks, but coupling into a prototype railcar even with the brakes released is like hitting a brick wall. 

[nscaleSPF2]

Group:
As I noted in an earlier post to the original TSC thread, I tried modifying the coupler parts in hopes to improve performance. The fingers of the two coupler parts average about .016" in thickness. I tried thinning the >inside< in 0.02 increments with continual testing as I thinned. Once the inside of each finger was thinned to approximately 0.010" ease of coupling improved significantly, there was no longer any "snap" and they coupled with similar ease as the normal MT couplers. I then tested them for disconnects under load and did not experience any at all at the 0.010" thickness. That is the good news.

The bad news was that although the couplers coupled perfectly, without resistance, when perfectly aligned facing each other, in normal operation, given the lateral movement in most cars due to various tolerances in wheel sets, rail gauge etc., the face of the "hook" of the coupler is not sufficiently wide to cover potential lateral tolerances. In other words, if I aligned the two cars facing each other by hand, they would couple perfectly. When I had the cars pushed together by a locomotive, the coupling only occured about 5% of the time, and then only on straight track. Basically the hooks would not engage sufficiently to slide laterally and thence engage. And last, even with the thinned fingers, lateral movement was insufficient and resulted in some 40' NMRA weighted cars rocking on 14" curvatures.

Bill, I'm not sure why you removed material from the inside of the fingers, but I think that this will prevent the couplers from being aligned (laterally) when you try to couple them.  I stress the word "think".  In my experience, I removed material only from the outside of the knuckle finger and did not have the problems that you experienced.  I can't explain this, exactly, but of course your results may vary.